[sirbruce]

Originally Posted by Dylrob

Interjection.
1. A sudden, short utterance; an ejaculation.
2. (Abbr. interj. or int.)

1. The part of speech that usually expresses emotion and is capable of standing alone.
2. Any of the words belonging to this part of speech, such as Ugh! or Wow!

http://www.school-house-rock.com/Int.html